وَيَسْرُبُ مِنْ يَتْبَعُهُ، لِكَيْ يَجْهَلَ مَرْبَعَهُ
He slipped away from anyone who followed so that the follower would not learn his lodging.
Yasrubu means to slip away or escape quietly; yatbaʿuhu describes a follower; marbaʿ denotes a resting place or dwelling in this context.
The clause li-kay yajhala specifies intention: he moves in a way designed to prevent discovery of where he stays.